Ocular Implant Architectures

ABSTRACT

An ocular implant having a first spine; a second spine; a first strut extending in an axial direction Z between the first spine and the second spine; a second strut extending in an axial direction Z between the first spine and the second spine; wherein an angular dimension θ of a first edge of each strut undulates as the strut extends in the axial direction Z between the first spine and the second spine; and wherein a radius r of an outer surface of each strut remains substantially constant as the strut extends the axial direction Z between the first spine and the second spine.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.11/860,318, filed Sep. 24, 2007, and claims priority to U.S. ProvisionalApplication No. 61/033,746, filed Mar. 4, 2008, the disclosures of whichare incorporated by reference as if fully set forth herein.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

FIELD OF THE INVENTION

The present invention relates generally to devices that are implantedwithin the eye. More particularly, the present invention relates todevices that facilitate the transfer of fluid from within one area ofthe eye to another area of the eye.

BACKGROUND OF THE INVENTION

According to a draft report by The National Eye Institute (NEI) at TheUnited States National Institutes of Health (NIH), glaucoma is now theleading cause of irreversible blindness worldwide and the second leadingcause of blindness, behind cataract, in the world. Thus, the NEI draftreport concludes, “it is critical that significant emphasis andresources continue to be devoted to determining the pathophysiology andmanagement of this disease.” Glaucoma researchers have found a strongcorrelation between high intraocular pressure and glaucoma. For thisreason, eye care professionals routinely screen patients for glaucoma bymeasuring intraocular pressure using a device known as a tonometer. Manymodern tonometers make this measurement by blowing a sudden puff of airagainst the outer surface of the eye.

The eye can be conceptualized as a ball filled with fluid. There are twotypes of fluid inside the eye. The cavity behind the lens is filled witha viscous fluid known as vitreous humor. The cavities in front of thelens are filled with a fluid know as aqueous humor. Whenever a personviews an object, he or she is viewing that object through both thevitreous humor and the aqueous humor.

Whenever a person views an object, he or she is also viewing that objectthrough the cornea and the lens of the eye. In order to be transparent,the cornea and the lens can include no blood vessels. Accordingly, noblood flows through the cornea and the lens to provide nutrition tothese tissues and to remove wastes from these tissues. Instead, thesefunctions are performed by the aqueous humor. A continuous flow ofaqueous humor through the eye provides nutrition to portions of the eye(e.g., the cornea and the lens) that have no blood vessels. This flow ofaqueous humor also removes waste from these tissues.

Aqueous humor is produced by an organ known as the ciliary body. Theciliary body includes epithelial cells that continuously secrete aqueoushumor. In a healthy eye, a stream of aqueous humor flows out of theanterior chamber of the eye through the trabecular meshwork and intoSchlemm's canal as new aqueous humor is secreted by the epithelial cellsof the ciliary body. This excess aqueous humor enters the venous bloodstream from Schlemm's canal and is carried along with the venous bloodleaving the eye.

When the natural drainage mechanisms of the eye stop functioningproperly, the pressure inside the eye begins to rise. Researchers havetheorized prolonged exposure to high intraocular pressure causes damageto the optic nerve that transmits sensory information from the eye tothe brain. This damage to the optic nerve results in loss of peripheralvision. As glaucoma progresses, more and more of the visual field islost until the patient is completely blind.

In addition to drug treatments, a variety of surgical treatments forglaucoma have been performed. For example, shunts were implanted todirect aqueous humor from the anterior chamber to the extraocular vein(Lee and Scheppens, “Aqueous-venous shunt and intraocular pressure,”Investigative Opthalmology (February 1966)). Other early glaucomatreatment implants led from the anterior chamber to a sub-conjunctivalbleb (e.g., U.S. Pat. No. 4,968,296 and U.S. Pat. No. 5,180,362). Stillothers were shunts leading from the anterior chamber to a point justinside Schlemm's canal (Spiegel et al., “Schlemm's canal implant: a newmethod to lower intraocular pressure in patients with POAG?” OphthalmicSurgery and Lasers (June 1999); U.S. Pat. No. 6,450,984; U.S. Pat. No.6,450,984).

SUMMARY OF THE INVENTION

One aspect of the invention provides an ocular implant having a firstspine; a second spine; a first strut extending in an axial direction Zbetween the first spine and the second spine; a second strut extendingin an axial direction Z between the first spine and the second spine;wherein an angular dimension θ of a first edge of each strut undulatesas the strut extends in the axial direction Z between the first spineand the second spine; and wherein a radius r of an outer surface of eachstrut remains substantially constant as the strut extends the axialdirection Z between the first spine and the second spine.

Yet another aspect of the invention provides an ocular implant having afirst spine section; a second spine section; and a first frame extendingbetween the first spine section and the second spine section, the framehaving a diameter of between 0.005 inches and 0.04 inches, the ocularimplant being adapted to be disposed within a canal of Schlemm in ahuman eye.

In some embodiments, the first spine section, the second spine section,and the first frame form portions of a single tubular wall. Each spinesection may optionally have only a single spine. In some embodiments,each spine section has an arcuate shape in lateral cross section. Insome embodiments, the first spine has a first circumferential extent andthe first frame has a second circumferential extent, wherein the secondcircumferential extent is greater than the first circumferential extent.

In some embodiments, the first frame has a first strut and a secondstrut and may have only two struts. Each strut may optionally have anarcuate shape in lateral cross section.

In embodiments in which the first strut has a first edge (partiallydefining, e.g., a first opening in the ocular implant), an angulardimension θ of the first edge may undulate as the strut extends in anaxial direction Z between the first spine and the second spine. Anangular dimension θ of the first edge may also first increase, thendecrease, as the strut extends in an axial direction Z between the firstspine and the second spine. Also, a radius r of the first edge mayremain substantially constant as the strut extends in axial dimension Zbetween the first spine and the second spine.

In some embodiments, the first strut has a thickness that issubstantially constant in a radial direction. In some embodiments, thefirst strut has a width extending in an arc along a circumferentialdirection. In some embodiments, the first strut has a length extendingin an axial direction that is generally parallel to a longitudinal axisof the ocular implant.

The first spine section and the second spine section may be axiallyaligned with one another. A shape of the second strut may also be amirror image of a shape of the first strut.

Some embodiments of the ocular implant have a second frame extendingbetween the second spine and a third spine. Some embodiments of theocular implant have a first opening extending between the first edge ofthe first strut and the first edge of the second strut. In someembodiments, a second edge of the first strut and a second edge of thesecond strut defining a second opening. In some embodiments, the firststrut, the second strut, the first spine section, and the second spinesection all define a cylindrical volume.

Some embodiments of the ocular implant have a therapeutic agent (e.g.,an anti-glaucoma drug such as a prostaglandin analog like latanprost)deposited on the frame and spine sections.

Still another aspect of the invention provides an ocular implant havinga first spine; a second spine; a first frame comprising a first strutand a second strut; each strut extending in an axial direction Z betweenthe first spine and the second spine; a first opening of the ocularimplant extending between a first edge of the first strut and a firstedge of the second strut; a second edge of the first strut and a secondedge of the second strut defining a second opening; wherein an angulardimension θ of the first edge of each strut undulates as the strutextends in the axial direction Z between the first spine and the secondspine; and wherein a radius r of an outer surface of each strut remainssubstantially constant as the strut extends the axial direction Zbetween the first spine and the second spine.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view showing a body that may be used to form anocular implant in accordance with one exemplary embodiment of theinvention. The body comprises a first spine, a second spine, and a firstframe disposed between the first spine and the second spine. The firstframe comprises a first strut and a second strut.

FIG. 2 is an isometric view of the body shown in the previous figure. Inthe embodiment of FIG. 2, the body is shaped to form an ocular implanthaving an outer surface defining a generally cylindrical volume. Aninner surface of the body defines an elongate channel. The ocularimplant may be inserted into Schlemm's canal of a human eye tofacilitate the flow of aqueous humor out of the anterior chamber.

FIG. 3A is a plan view showing a portion of the ocular implant shown inthe previous figure. The ocular implant includes a first framecomprising a first strut and a second strut. In the exemplary embodimentof FIG. 3A, each strut undulates in a circumferential direction while,at the same time, extending in the axial direction Z between a firstspine and a second spine.

FIG. 3B is a lateral cross-sectional view of the ocular implant shown inthe previous figure. Section line B-B intersects the first strut andsecond strut of the ocular implant at the point where thecircumferential undulation of these struts is at it's maximum. Thesestruts form a frame having circumferential extent that is illustratedusing dimension lines in FIG. 3B.

FIG. 3C is a lateral cross-sectional view of the ocular implant of FIG.3A taken along section line C-C. Section line C-C intersects a spine ofthe ocular implant at the point where the width of the spine is at aminimum. A circumferential extent of the spine illustrated usingdimension lines in FIG. 3C. With reference to FIG. 3C and FIG. 3B, itwill be appreciated that the circumferential extent of frame is greaterthan the circumferential extent of the spine.

FIG. 4 is an isometric view showing a portion of the ocular implantshown in the previous figure. With reference to FIG. 4, it will beappreciated that the outer surfaces of the first spine, the secondspine, the first strut, and the second strut define a generallycylindrical volume V. The shape of the ocular implant may be describedusing the cylindrical coordinates shown in FIG. 4.

FIG. 5 is an enlarged plan view showing a portion of the ocular implantshown in the previous figure. In FIG. 5, a number of section lines areshown crossing the first strut and the second strut of the ocularimplant. In the embodiment of FIG. 5, each strut undulates in acircumferential direction while, at the same time, extending in axialdirection Z between the first spine and the second spine. Thecircumferential undulation of the first strut is illustrated in FIG. 6using lateral cross-sectional drawings labeled with cylindricalcoordinates.

FIG. 6A through 6E are lateral cross-sectional views of the ocularimplant shown in the previous figure. These cross-sectional viewscorrespond to the section lines shown in the previous figure. Withreference to these cross-sectional views, it will be appreciated thatthe angular dimension θ associated with a first edge of the first strutundulates as the first strut extends in an axial direction Z between thefirst spine and the second spine. In the embodiment of FIG. 6, theradius r of the outer surface of the first strut remains substantiallyconstant as the first strut extends in the axial direction Z between thefirst spine and the second spine.

FIG. 7 shows a plurality of cylindrical coordinate values correspondingwith the cross-sectional views shown in the previous figure.

FIG. 8 is an isometric view of an ocular implant in accordance with anadditional exemplary embodiment of the invention.

FIG. 9 is a plan view of the ocular implant shown in the previousfigure. In the embodiment of FIG. 9, the ocular implant has an at restshape that is generally curved.

FIG. 10 shows the ocular implant of the previous figure in place withina human eye.

FIG. 11 is an enlarged plan view showing a portion of the eye shown inthe previous figure.

DETAILED DESCRIPTION

The following detailed description should be read with reference to thedrawings, in which like elements in different drawings are numberedidentically. The drawings, which are not necessarily to scale, depictexemplary embodiments and are not intended to limit the scope of theinvention. Examples of constructions, materials, dimensions, andmanufacturing processes are provided for selected elements. All otherelements employ that which is known to those of skill in the field ofthe invention. Those skilled in the art will recognize that many of theexamples provided have suitable alternatives that can be utilized.

FIG. 1 is an isometric view showing a body 100 that may be used to forman ocular implant in accordance with one exemplary embodiment of theinvention. Body 100 comprises a first spine 102, a second spine 104, anda first frame 106 disposed between first spine 102 and second spine 104.In the embodiment of FIG. 1, first frame 106 comprises a first strut 120and a second strut 122. With reference to FIG. 1, it will be appreciatedthat each strut extends between first spine 102 and second spine 104.

First strut 120 of first frame 106 comprises a first edge 124A and asecond edge 126A. With reference to FIG. 1, it will be appreciated thatsecond strut 122 has a shape that is a mirror image of the shape offirst strut 120. Second strut 122 comprises a first edge 124B and asecond edge 126B. Second edge 126B of second strut 122 and second edge126A of first strut 120 define a second opening 130. Second opening 130generally divides first frame 106 into first strut 120 and second strut122.

With continuing reference to FIG. 1, it will be appreciated that body100 comprises a plurality of spines and a plurality of frames. In theembodiment of FIG. 1, these spines and frames are arranged in an ABABpattern. Each spine has a first lateral extent 132 and each frame has asecond lateral extent 134. With reference to FIG. 1, it will beappreciated that second lateral extent 134 is greater than first lateralextent 132.

FIG. 2 is an isometric view of body 100 shown in the previous figure. Inthe embodiment of FIG. 2, body 100 is shaped to form an ocular implant136 having an outer surface 138 defining a generally cylindrical volume.An inner surface 140 of body 100 defines an elongate channel 142. Ocularimplant 136 may be inserted into Schlemm's canal of a human eye tofacilitate the flow of aqueous humor out of the anterior chamber. Thisflow may include axial flow along Schlemm's canal, flow from theanterior chamber into Schlemm's canal, and flow leaving Schlemm's canalvia outlets communicating with Schlemm's canal. When in place within theeye, ocular implant 136 will support trabecular mesh tissue andSchlemm's canal tissue and will provide for improved communicationbetween the anterior chamber and Schlemm's canal (via the trabecularmeshwork) and between pockets or compartments along Schlemm's canal.

Elongate channel 142 of ocular implant 136 fluidly communicates with afirst opening 128 as well as inlet portion 101. Various fabricationtechniques may be used to fabricate ocular implant 136. For example,ocular implant 136 can be fabricated by providing a generally flat sheetof material and laser cutting the sheet of material to form body 100shown in FIG. 1. The body 100 may then be formed into a generallytubular shape as shown in FIG. 2. Any adjoining edges (such as edges103) may be, optionally, welded. By way of a second example, ocularimplant 136 may be fabricated by providing a tube and laser cuttingopenings in the tube to form the shape shown in FIG. 2.

As shown in FIG. 2, ocular implant 136 comprises a first spine 102 and asecond spine 104. A first frame 106 of ocular implant 136 is disposedbetween first spine 102 and second spine 104. In the embodiment of FIG.2, first frame 106 comprises a first strut 120 that extends betweenfirst spine 102 and second spine 104. First frame 106 also comprises asecond strut 122. Second strut 122 also extends between first spine 102and second spine 104.

First strut 120 of first frame 106 comprises a first edge 124A and asecond edge 126A. Second strut 122 has a shape that is a mirror image ofthe shape of first strut 120. In FIG. 2, first opening 128 of ocularimplant 136 can be seen extending between first edge 124A of first strut120 and a first edge 124B of second strut 122. A second edge 126B ofsecond strut 122 and second edge 126A of first strut 120 define a secondopening 130. Second opening 130 and additional openings (e.g., firstopening 128) defined by ocular implant 136 allow aqueous humor to flowlaterally across and/or laterally through ocular implant 136.

Ocular implant 136 can be fabricated from various biocompatiblematerials possessing the necessary structural and mechanical attributes.Both metallic and non-metallic materials may be suitable. Examples ofmetallic materials include stainless steel, tantalum, gold, titanium,and nickel-titanium alloys known in the art as Nitinol. Nitinol iscommercially available from Memry Technologies (Brookfield, Conn.), TiNiAlloy Company (San Leandro, Calif.), and Shape Memory Applications(Sunnyvale, Calif.).

Ocular implant 136 may include one or more therapeutic agents. One ormore therapeutic agents may, for example, be incorporated into apolymeric coating that is deposited onto the outer surfaces of thestruts and spines of the ocular implant. The therapeutic agent maycomprise, for example, an anti-glaucoma drug. Examples of anti-glaucomadrugs include prostaglandin analogs. Examples of prostaglandin analogsinclude latanprost.

FIG. 3A is a plan view showing a portion of ocular implant 136 shown inthe previous figure. Body 100 of ocular implant 136 comprises a firstspine 102, a second spine 104, and a first frame 106 disposed betweenfirst spine 102 and second spine 104. In the embodiment of FIG. 3A,first frame 106 comprises a first strut 120 and a second strut 122. Asshown, each strut undulates in a circumferential direction while, at thesame time, extending in the axial direction Z between first spine 102and second spine 104.

FIG. 3B is a lateral cross-sectional view of ocular implant 136 takenalong section line B-B. Section line B-B intersects first strut 120 andsecond strut 122 at the point where the circumferential undulation ofthese struts is at its maximum. First strut 120 and second strut 122form first frame 106. First frame 106 has a first circumferential extent144 in the embodiment of FIG. 3B.

FIG. 3C is a lateral cross-sectional view of ocular implant 136 takenalong section line C-C. Section line C-C intersects first spine 102 atthe point where the width of first spine 102 is at a minimum. At thispoint, first spine 102 has a second circumferential extent 146. Secondcircumferential extent 146 of first spine 102 is illustrated usingdimension lines in FIG. 3C. With reference to FIG. 3C and FIG. 3B, itwill be appreciated that first circumferential extent 144 of first frame106 is greater than second circumferential extent 146 of first spine102.

FIG. 4 is an isometric view showing a portion of ocular implant 136shown in the previous figure. With reference to FIG. 4, it will beappreciated that the outer surfaces of first spine 102, second spine104, first strut 120, and second strut 122 define a portion of agenerally cylindrical volume V. The shape of ocular implant 136 may bedescribed using the cylindrical coordinates shown in FIG. 4. Thesecylindrical coordinates include a radius r, an angle θ and an axialdimension Z. Cylindrical coordinates may be conceptualized as anextension of two dimensional polar coordinates to include a longitudinalor axial dimension Z. The two dimensions of a typical polar coordinatesystem are radius r and angle θ. In the embodiment of FIG. 4, dimensionZ extends along a longitudinal axis 148 of cylindrical volume V.

As shown in FIG. 4, first strut 120 extends in axial direction Z betweenfirst spine 102 and second spine 104. Second strut 122 also extendsbetween first spine 102 and second spine 104. In the embodiment of FIG.4, the radius r of the outer surface of each strut remains substantiallyconstant. The angular dimension θ of a first edge 124A of first strutvaries as first strut 120 extends in the axial direction Z between firstspine 102 and second spine 104. Similarly, the angular dimension θ of asecond edge 126A of second strut varies as second strut 122 extends inthe axial direction Z between first spine 102 and second spine 104.

FIG. 5 is an enlarged plan view showing a portion of ocular implant 136shown in the previous figure. In FIG. 5, a number of section lines areshown crossing first strut 120 and second strut 122 of ocular implant136. In the embodiment of FIG. 5, each strut undulates in acircumferential direction while, at the same time, extending in axialdirection Z between first spine 102 and second spine 104. Thecircumferential undulation of first strut 120 is illustrated in the nextfigure using lateral cross-sectional drawings labeled with cylindricalcoordinates.

FIG. 6A through 6E are lateral cross-sectional views of ocular implant136 shown in the previous figure. These cross-sectional views correspondto the section lines shown in the previous figure. With reference tothese cross-sectional views, it will be appreciated that the angulardimension θ associated with first edge 124A of first strut 120 undulatesas first strut 120 extends in an axial direction Z between the firstspine and the second spine. In the embodiment of FIG. 6, the radius r ofthe outer surface of first strut 120 remains substantially constant asfirst strut 120 extends in axial direction Z between the first spine andthe second spine.

FIG. 7 shows a plurality of cylindrical coordinate values correspondingwith the cross-sectional views shown in the previous figure. Withreference to the numerical values shown in FIG. 7, it will beappreciated that the numerical value of angular dimension θ of firstedge 124 first increases, then decreases, as first strut 120 extends inan axial direction Z between the first spine and the second spine. Thenumerical value r remains constant as first strut 120 extends in axialdirection Z between the first spine and the second spine.

FIG. 8 is an isometric view of an ocular implant 236 in accordance withan additional exemplary embodiment of the invention. As shown in FIG. 8,ocular implant 236 comprises a first spine 202 and a second spine 204. Afirst frame 206 of ocular implant 236 is disposed between first spine202 and second spine 204. In the embodiment of FIG. 8, first frame 206comprises a first strut 220 that extends between first spine 202 andsecond spine 204. First frame 206 also comprises a second strut 222.With reference to FIG. 8, it will be appreciated that second strut 222also extends between first spine 202 and second spine 204.

Ocular implant 236 of FIG. 8 defines a channel 242 that opens into afirst opening 228. In FIG. 8, first opening 228 of ocular implant 236can be seen extending between first strut 220 and second strut 222.First strut 220 and second strut 222 also define a second opening 230.First opening 228, second opening 230, and the additional openings shownin FIG. 8, allow aqueous humor to flow laterally across and/or laterallythrough ocular implant 236.

In the embodiment of FIG. 8, an inlet portion 250 is formed near aproximal end of ocular implant 236. Inlet portion 250 may extend throughthe trabecular meshwork into the anterior chamber of the eye when aportion of the ocular implant lies in Schlemm's canal.

In the embodiment of FIG. 8, a blunt tip 252 is disposed at a distal endof ocular implant 236. In some useful embodiments of ocular implant 236,blunt tip 252 has a generally rounded shape. In the embodiment shown inFIG. 8, blunt tip 252 has a generally hemispherical shape. The generallyrounded shape of blunt tip 252 may increase the likelihood that body 200will track Schlemm's canal as ocular implant 236 is advanced into thecanal during an implant procedure.

In FIG. 8, ocular implant 236 is pictured assuming a generally straightshape. Embodiments of ocular implant 236 are possible which have agenerally curved resting shape. Ocular implant 236 may be fabricated,for example, by laser cutting a tube to create the shape shown in FIG.8. When this is the case, it may be desirable to rotate a straighttubular workpiece during the laser cutting process. After the lasercutting process, the ocular implant can be heat-set so that the ocularimplant is biased to assume a selected shape (e.g., a generally curvedshape).

FIG. 9 is a plan view of ocular implant 236 shown in the previousfigure. In the embodiment of FIG. 9, ocular implant 236 has an at restshape that is generally curved. This at rest shape can be established,for example, using a heat-setting process. The ocular implant shapeshown in FIG. 9 includes a distal radius RA, a proximal radius RC, andan intermediate radius RB. In the embodiment of FIG. 9, distal radius RAis larger than both intermediate radius RB and proximal radius RC. Alsoin the embodiment of FIG. 9, intermediate radius RB is larger thanproximal radius RC and smaller than distal radius RA. In one usefulembodiment, distal radius RA is about 0.310 inches, intermediate radiusRB is about 0.215 inches and proximal radius RC is about 0.105 inches.

In the embodiment of FIG. 9, a distal portion of the ocular implantfollows distal radius RA along an arc extending across an angle AA. Aproximal portion of the ocular implant follows proximal radius RC alongan arc extending across an angle AC. An intermediate portion of theocular implant is disposed between the proximal portion and the distalportion. The intermediate portion follows radius RB and extends acrossan angle AB. In one useful embodiment, angle AA is about 55 degrees,angle AB is about 79 degrees and angle AC is about 60 degrees.

Ocular implant 236 may be used in conjunction with a method of treatinga patient. Some such methods may include the step of inserting a coremember into a lumen defined by ocular implant 236. The core member maycomprise, for example, a wire or tube. The distal end of the ocularimplant may be inserted into Schlemm's canal. The ocular implant and thecore member may then be advanced into Schlemm's canal until the ocularimplant has reached a desired position. The core member may then bewithdrawn from the ocular implant.

FIG. 10 shows ocular implant 236 of the previous figure in place withina human eye. The eye of FIG. 10 includes an anterior chamber that iscovered by a cornea. The iris of the eye is visible through the corneaand the anterior chamber. The anterior chamber is filled with aqueoushumor which helps maintain the generally hemispherical shape of thecornea.

Whenever a person views an object, he or she is viewing that objectthrough the cornea, the aqueous humor, and the lens of the eye. In orderto be transparent, the cornea and the lens can include no blood vessels.Accordingly, no blood flows through the cornea and the lens to providenutrition to these tissues and to remove wastes from these tissues.Instead, these functions are performed by the aqueous humor. Acontinuous flow of aqueous humor through the eye provides nutrition toportions of the eye (e.g., the cornea and the lens) that have no bloodvessels. This flow of aqueous humor also removes waste from thesetissues.

Aqueous humor is produced by an organ known as the ciliary body. Theciliary body includes epithelial cells that continuously secrete aqueoushumor. In a healthy eye, a stream of aqueous humor flows out of the eyeas new aqueous humor is secreted by the epithelial cells of the ciliarybody. This excess aqueous humor enters the blood stream and is carriedaway by venous blood leaving the eye.

The structures that drain aqueous humor from the anterior chamberinclude Schlemm's canal and a large number of veins that communicatewith Schlemm's canal via a plurality of outlets. In FIG. 10, Schlemm'scanal 20 can be seen encircling the iris of the eye. Ocular implant 236may be inserted into Schlemm's canal 20 to facilitate the flow ofaqueous humor out of the anterior chamber. This flow may include axialflow along Schlemm's canal, flow from the anterior chamber intoSchlemm's canal, and flow leaving Schlemm's canal via outletscommunicating with Schlemm's canal. When in place within the eye, ocularimplant 236 will support trabecular mesh tissue and Schlemm's canaltissue and will provide for improved communication between the anteriorchamber and Schlemm's canal (via the trabecular meshwork) and betweenpockets or compartments along Schlemm's canal.

FIG. 11 is an enlarged plan view showing a portion of the eye shown inthe previous figure. With reference to FIG. 11, it will be appreciatedthat ocular implant 236 extends through Schlemm's canal 20 across anangle G. Various implant sizes are possible, and different implant sizesmay span a different angle G when placed in Schlemm's canal. Examples ofangular spans that may be suitable in some applications include 60°,90°, 150° and 180°.

In FIG. 11, an inlet portion 250 of ocular implant 236 is shownextending through trabecular mesh 22. Aqueous humor may exit anteriorchamber 24 and enter Schlemm's canal 20 by flowing through inlet portion250 of ocular implant 236. Aqueous humor may also exit anterior chamber24 and enter Schlemm's canal 20 by flowing through the trabecular mesh22 of the eye. With reference to FIG. 11, it will be appreciated thatthe spines of ocular implant 236 support trabecular mesh 22.

Aqueous humor exits Schlemm's canal 20 by flowing through a number ofoutlets. After leaving Schlemm's canal 20, aqueous humor travels througha network passages and veins and is absorbed into the blood stream.Schlemm's canal typically has a non-circular cross-sectional shape whosediameter can vary along the canal's length and according to the angle atwhich the diameter is measured. In addition, there may be multiplepartial pockets or partial compartments (not shown in these figures)formed along the length of Schlemm's canal. The shape and diameter ofportions of Schlemm's canal and the existence and relative location ofpartial pockets or compartments may limit or prevent fluid flow from onepoint of Schlemm's canal to another. Hence, each outlet from Schlemm'scanal may drain only a portion of Schlemm's canal. This condition may beimproved by placing ocular implant 236 in Schlemm's canal. Ocularimplant 236 shown in FIG. 11 includes a plurality of struts, spines andopenings. When in place within the eye, ocular implant 236 will supporttrabecular mesh tissue and Schlemm's canal tissue and will provide forimproved communication between the anterior chamber and Schlemm's canaland between pockets or compartments along Schlemm's canal.

In FIG. 11, first opening 228 of ocular implant 236 is shown facingradially outward in Schlemm's canal 20. Aqueous humor can exit Schlemm'scanal 20 by flowing through outlets that radiate away from andcommunicate with Schlemm's canal 20. After flowing through theseoutlets, this excess aqueous humor can enter the venous bloodstream becarried out of the eye by venous blood flow. The diameter of ocularimplant 236 can range from 0.005 inches to 0.04 inches, preferably from0.005 inches to 0.02 inches, in order to lie within and supportSchlemm's canal.

While exemplary embodiments of the present invention have been shown anddescribed, modifications may be made, and it is therefore intended inthe appended claims to cover all such changes and modifications whichfall within the true spirit and scope of the invention.

1. An ocular implant, comprising: a first spine; a second spine; a firststrut extending in an axial direction Z between the first spine and thesecond spine; a second strut extending in an axial direction Z betweenthe first spine and the second spine; wherein an angular dimension θ ofa first edge of each strut undulates as the strut extends in the axialdirection Z between the first spine and the second spine; and wherein aradius r of an outer surface of each strut remains substantiallyconstant as the strut extends the axial direction Z between the firstspine and the second spine.
 2. An ocular implant, comprising: a firstspine section; a second spine section; a first frame extending betweenthe first spine section and the second spine section, the frame having adiameter of between 0.005 inches and 0.04 inches; the ocular implantbeing adapted to be disposed within a canal of Schlemm in a humansubject's eye.
 3. The ocular implant of claim 2, wherein the first spinesection, the second spine section, and the first frame comprise portionsof a single tubular wall.
 4. The ocular implant of claim 2, wherein eachspine section comprises only a single spine.
 5. The ocular implant ofclaim 2, wherein each spine section has an arcuate shape in lateralcross section.
 6. The ocular implant of claim 2, wherein: the firstspine has a first circumferential extent; and the first frame has asecond circumferential extent; wherein the second circumferential extentis greater than the first circumferential extent.
 7. The ocular implantof claim 2, wherein the first frame comprises a first strut and a secondstrut.
 8. The ocular implant of claim 7, wherein the first framecomprises only two struts.
 9. The ocular implant of claim 7, whereineach strut has an arcuate shape in lateral cross section.
 10. The ocularimplant of claim 7, wherein the first strut comprises a first edge. 11.The ocular implant of claim 10, wherein an angular dimension θ of thefirst edge undulates as the strut extends in an axial direction Zbetween the first spine and the second spine.
 12. The ocular implant ofclaim 10, wherein an angular dimension θ of the first edge firstincreases, then decreases, as the strut extends in an axial direction Zbetween the first spine and the second spine.
 13. The ocular implant ofclaim 10, wherein a radius r of the first edge remains substantiallyconstant as the strut extends in axial dimension Z between the firstspine and the second spine.
 14. The ocular implant of claim 10, whereinthe first edge partially defines a first opening in the ocular implant.15. The ocular implant of claim 7, wherein the first strut has athickness that is substantially constant in a radial direction.
 16. Theocular implant of claim 7, wherein the first strut has a width extendingin an arc along a circumferential direction.
 17. The ocular implant ofclaim 7, wherein the first strut has a length extending in an axialdirection that is generally parallel to a longitudinal axis of theocular implant.
 18. The ocular implant of claim 7, wherein the firstspine section and the second spine section are axially aligned with oneanother.
 19. The ocular implant of claim 7, wherein a shape of thesecond strut is a mirror image of a shape of the first strut.
 20. Theocular implant of claim 7, further comprising a second frame extendingbetween the second spine and a third spine.
 21. The ocular implant ofclaim 7, wherein a second edge of the first strut and a second edge ofthe second strut defining a second opening.
 22. The ocular implant ofclaim 7, wherein the first strut, the second strut, the first spinesection, and the second spine section all define a cylindrical volume.23. The ocular implant of claim 7, further comprising a first openingextending between the first edge of the first strut and the first edgeof the second strut.
 24. The implant of claim 2 further comprising atherapeutic agent deposited on the frame and spine sections.
 25. Theimplant of claim 24 wherein the therapeutic agent comprises ananti-glaucoma drug.
 26. The implant of claim 25 wherein theanti-glaucoma drug comprises a prostaglandin analog.
 27. The implant ofclaim 26 wherein the prostaglandin analog comprises latanprost.
 28. Anocular implant, comprising: a first spine; a second spine; a first framecomprising a first strut and a second strut; each strut extending in anaxial direction Z between the first spine and the second spine; a firstopening of the ocular implant extending between a first edge of thefirst strut and a first edge of the second strut; a second edge of thefirst strut and a second edge of the second strut defining a secondopening; wherein an angular dimension θ of the first edge of each strutundulates as the strut extends in the axial direction Z between thefirst spine and the second spine; and wherein a radius r of an outersurface of each strut remains substantially constant as the strutextends the axial direction Z between the first spine and the secondspine.